The present invention relates to a system for insuring that an upper bearing of a duplex bearing system is provided with an adequate supply of a lubricant and to a spacer arrangement for use in a duplex bearing system. The spacer arrangement of the present invention has particular utility in swashplate systems used on helicopters.
Swashplate systems used in helicopters currently use a duplex bearing system such as that shown in FIG. 1. As shown therein, the swashplate system 10 includes a stationary swashplate 12, a rotating swashplate 14, and a duplex bearing system 16 between the two. The duplex bearing system has an upper bearing 18 and a lower bearing 20. A chamber 22 is situated between the upper bearing 18 and a lower bearing 20 and is supplied with a lubricant such as grease via an inlet 24 and a grease gun (not shown). The chamber 22 has a set of spacers 26 and 28 which separate the bearings so that they can better resist control moments from the pushrods.
In this swashplate system, the initial pressure from the grease gun is relied upon to overcome gravity and force grease into the cavity 30 for the upper bearing 18. The disadvantage of this system is that after the initial application gravity tends to remove the lubricant from the upper bearing cavity 30.